Know exactly what to charge.

Who these calculators are for

These tools are built for people who work for themselves: freelancers billing by the hour, contractors on day rates, consultants pricing fixed-scope projects, and one-person businesses that handle their own invoicing and financial tracking. They are not designed for corporate finance teams or large-scale accounting — they are designed for one person at a desk trying to work out what to charge, what to set aside, and whether the numbers add up.

The most common situation they address is the gap between revenue and financial clarity. A freelancer might invoice $8,000 in a month and still feel uncertain about what they actually keep after tax and expenses, whether that amount covers their costs at the rate they charged, and whether they would hit break-even if the next month was slower. These calculators make that arithmetic visible.

They work for any country and any currency. No rates, percentages or official figures from any government or institution are built into the calculations. You bring the rate that applies to your situation — whether that is a UK VAT rate, a US self-employment tax rate, an Australian GST rate, or something else entirely — and the calculator applies it to the numbers you enter.

What "pure arithmetic" means in practice

Every calculator on this site applies a formula to the numbers you type in. Nothing else happens. There is no database lookup, no connection to a government API, no retrieval of current rates or published figures. The result you see is a direct mathematical consequence of the inputs you provide — no more, no less.

This approach has one important implication: the accuracy of the output depends entirely on the accuracy of the input. A correct formula applied to an incorrect input produces an incorrect output. If you enter a tax rate that does not apply to your situation, or an expense figure that is incomplete, the result will be off by the same amount. The calculator cannot detect or correct for this. The formula is shown with every result so you can verify it yourself, but the inputs are your responsibility.

Where a calculator displays a default value — a suggested rate or a typical cost — that default is there to illustrate the formula with a concrete example. It is a starting point, not an authoritative figure. Replace it with the number that applies to your situation before you act on the result.

How the four categories work together

The tools are grouped into four categories that represent the financial decisions a one-person business faces most often.

Pricing and rates is where most decisions start. The hourly rate calculator works out the minimum you need to charge per billable hour to cover your income target, your costs and your tax set-aside. That rate then feeds into the day rate and project quote calculators, which translate the hourly floor into per-day and per-project prices. The markup and profit margin calculators measure whether the resulting price contains the profit you intended.

Taxes covers the estimation side of self-employment tax obligations: how much to set aside for payroll-style contributions, how to split that into quarterly instalments, and what the take-home looks like after both layers of tax are subtracted. Every tax calculator lets you enter your own rates, because the rates that apply depend on your country and situation — not on anything built into this site.

Invoicing and payments handles the arithmetic of sending an invoice and collecting payment: the total including discount and tax in the right order, the amount that reaches your account after a payment-processor fee, and the interest owed if a payment is late.

Business health takes a wider view: your break-even point in units and revenue, your net profit after all costs and taxes, and your billable-hour utilisation rate — how much of your working time is actually generating income.

Limits of these tools

These are planning tools, not professional services. They produce estimates from the numbers you provide. They do not take into account your full tax situation, applicable deductions, legal structure, jurisdiction-specific rules, or any other factor outside what you enter. Where a decision has significant financial consequences — setting prices for a major contract, filing a tax return, taking on debt — verify the numbers with a qualified professional who knows your specific situation.

Default values in the calculators are illustrative. Market rates for your field, region, and experience level are something only you can research. Rates that apply to your legal and tax situation are something only a professional who knows that situation can confirm. The calculator can check the arithmetic once you have the right inputs — finding those inputs is a separate step.